1. Field of the Invention
The present invention relates to an image forming device for analyzing a document to form an image of the document, which is written in a description language, such as Hyper Text Markup Language, or HTML, which allows acquisition of display content data of a document element from a place other than where the document element is described.
2. Description of the Related Art
Recent development of the World Wide Web, or WWW, has led to the rapid increase in the use of documents written in a markup language, such as HTML or XML (extensible Markup Language). For conventional printing of these documents, generally, a browser and a printer driver in a personal computer perform layout and page dividing for creation of a page image, which is then provided to a printer for printing.
In recent years, common use of personal data assistants, or PDAs, data transmitting mobile telephones, and so forth, has created an increased demand to send such an HTML document from a PDA or the like to a printer for printing. However, a PDA or the like is not adapted to holding a highly sophisticated printer driver or the like and may often suffer from a strict limitation of memory capacity.
In order to address these problems, there is proposed a print service in which an HTML document or the like is sent directly to a printer for printing (referred to as direct print) or a PDA or the like sends a uniform resource locater, or a URL, to a printer so that the printer can download the document identified by the URL for printing (referred to as pull-print).
Nowadays, XHTML-print is established as a standard specification for some standards, such as bluetooth and Universal Plug and Play, or UpnP, and is regarded as one of the essential languages for printers.
In order to print a document written in these languages, such as HTML and XHTML-print, since these languages do not have the concept of pages, a rendering size and layout of each document element must be determined before page dividing is applied to the document to fix page breaks.
Here, an XHTML-print document or the like may often include an element, such as an image, which refers to an outside file or a code within the document but in a different place (the latter referred to as an inline image). Because the rendering size of such an element is yet to be known at the time when the element is found based on a tag during analysis of the document, the element cannot be laid out until acquisition of its substantial data from a reference destination (the substantial data hereinafter referred to as display content data).
With the above as background, a conventional printer for printing a document written in XHTML-print or the like first analyzes the document and acquires display content data of all document elements found in the analysis and then rasterizes (rendering) for printing (see Japanese Patent Laid-open Publication No. Hei 10-074265).
However, this conventional printing in which printing is withheld until display content data of all document elements is acquired has a problem of delayed start of printing because data downloading from an outside reference destination may take time. Another problem of the conventional printing is the need for a large capacity work memory to hold display content data of all document elements, which increases cost.